The Mosaic Theory of the Fourth Amendment

In the Supreme Court’s recent decision on GPS surveillance, United States v. Jones, five justices authored or joined concurring opinions that applied a new approach to interpreting Fourth Amendment protection. Before Jones, Fourth Amendment decisions had always evaluated each step of an investigation individually. Jones introduced what we might call a “mosaic theory” of the Fourth Amendment, by which courts evaluate a collective sequence of government activity as an aggregated whole to consider whether the sequence amounts to a search. This Article considers the implications of a mosaic theory of the Fourth Amendment. It explores the choices and puzzles that a mosaic theory would raise, and it analyzes the merits of the proposed new method of Fourth Amendment analysis. The Article makes three major points. First, the mosaic theory represents a dramatic departure from the basic building block of existing Fourth Amendment doctrine. Second, adopting the mosaic theory would require courts to answer a long list of novel and challenging questions. Third, courts should reject the theory and retain the traditional sequential approach to Fourth Amendment analysis. The mosaic approach reflects legitimate concerns, but implementing it would be exceedingly difficult in light of rapid technological change. Courts can better respond to the concerns animating the mosaic theory within the traditional parameters of the sequential approach to Fourth Amendment analysis.